Blender 2.8 - Particle Instance not rendered
I know this is kind of old at this point but I just figured out this issue so I'm going to post how to make all the particle instances show up in case someone in the future needs help figuring it out.

In the Particle Instance modifier properties there is a check box for "Create Along Paths". Just make sure that is checked and they will show up. Easy fix that might not have been there in the betas for 2.8 but some of the tutorials I've watched so far seem to have left out this important part.